﻿/************************************************************************

   Extended Silverlight Toolkit

   Copyright (C) 2010-2012 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://extendedsilverlight.codeplex.com/license

   Please purchase a commercial version of this toolkit if you are using
   it in a commercial product. The commercial versions support the project,
   and also include more features for each control, priority support,
   source code, updates, removed watermark, and a proprietary license.

   Visit http://xceed.com and follow @datagrid on Twitter.

  **********************************************************************/

using System;

namespace Xceed.Silverlight.DataGrid
{
  internal class CleanUpVisitor : VisitorBase
  {
    public CleanUpVisitor(DataGridControl dataGrid)
      : base( ChildrenPolicy.RenderedChildrenOnly, true )
    {
      if( dataGrid == null )
        throw new ArgumentNullException( "dataGrid" );

      m_dataGrid = dataGrid;
    }

    public override void Visit( VirtualContainerBase containerBase )
    {
      base.Visit( containerBase );

      if( containerBase.Layout is ITransitionLayout )
      {
        ILayout newLayout = ( ( ITransitionLayout )containerBase.Layout ).NewLayout;

        LayoutUpdateResult result = containerBase.SetLayout( newLayout );

        foreach( ILayoutElement element in result.AddedElements )
        {
          m_dataGrid.RootHost.AddElement( element );
        }

        foreach( ILayoutElement element in result.RemovedElements )
        {
          m_dataGrid.ReleaseElement( element );
        }

        containerBase.CommitLayout();
      }
    }

    public override void Visit( WrapperBase wrapper )
    {
      LayoutTransitionHelper.EndTransition( wrapper );

      base.Visit( wrapper );
    }

    private DataGridControl m_dataGrid;
  }
}
